Improvement in tap-wrenches



1.1. GRANT.

lmprovement in Tap-Wrenches.

No. 129,472. Patentedluly 16,1872.

faemfeaf UNITED STATES PATENT OFFICE.

.JOHN J. GRANT, or GEEENFELD, MASSAGHUSETTS.

IMPROVEMENT IN TAP-WRENCHES.

Specification forming part of Letters Patent No. 129,472, dated July 16,1872.

Specification describing an Improved Tap- Wrench, invented by JOHN J.GRANT, of Greenfield, in the county of Franklin and State ofMassachusetts.

My improvement relates to that class of tapwrenches in which the jawsare rendered adjustable; and the nature thereof consists in certainimprovements in the details of the construction of the same hereinafterdescribed and shown. v

In the accompanying drawing, Figure 1 is a face view of a wrenchconstructed according to my invention. Fig. 2 is a longitudinal sectionof the same. Fig. 3 is a facial section of the same; and Fig. 1.1. is aview of a ring by which the jaws of the wrench are op erated.

Similar letters of reference indicate corresponding parts in the severalgures.

A is the stock of the wrench, which is provided with handles a a, in theusualmanner,

and has formed within it a longitudinal parallel-sided recess, b, inwhich the sliding jaws B B work. This recess is' intersected centrallyby a circular recess, c, within which there is iitted, above or outsidethe jaws B B, a ring, C, by which the jaws are operated, there being atthe bottom of this recess a central opening, g, in the stock, throughwhich the tap to be held is inserted to the jaws. Each jaw has formed init a right-angled notch, f, the two not-ches f f being intended toreceive opposite angles of the square head of the tap, or of any othersquare article, and so to hold it. The meeting-faces of said jaws areoblique to their length, so that throughout their adjustment a squareopening is preserved between them, and the said faces form bearings forthe whole width of two of the sides of the head of the top or othersquare article, the angles of which are received in the notches ff. Thering C has formed on its under side a spiral convolute thread, d, whichworks in corresponding grooves e e in the adjacent faces of the jaws BB. This ring has a milled periphery, portions of which project throughopenings c c, in opposite sides of the central recess c in the stock, toprovide for its manipulation by the thumb and iin gers to adjust thejaws. The ring, and the jaws too, are retained in place within the stockof the wrench by a cap-plate, G, which covers them, and which is securedto the stock by screws s s. This plate is provided with a central hole,h, corresponding with the one, g, in the stock.

To operate the wrench, the projecting portions of the milled peripheryof the ring C are manipulated to turn the ring, for the purpose ofmoving the jaws B B in or out, to adjust them to the size of the head ofthe tap or other article to be held. This is effected by the spiralcenvolute thread on the inner side of the ring working within the spiralgrooves in the jaws, and so moving them away from or toward each other.

I am aware that the jaws of wrenches have been rendered adjustable invarious ways, and that a disk provided with a spiral convolute ,ring hasbeen used for that purpose; (see the patent to J. D. Dale dated August2l, A. D. 1855 5) but the object of my invention is not only to producean adjustable wrench, but to so combine the parts constituting the sameas to facilitate the manufacture thereof, and enhance the conveniencewith which the implement may be used.

I therefore claim 'and desire to secure by Letters Patent- A tap-wrench,formed by the combination of the stock A having formed within it theparallel-sided 'recess b, 'intersected centrally by a circular recess,c, and provided with'openings c o and g; the jaws B provided withnotches f f and grooves e e; the annular thumb-piece O having a milledperiphery, and upon the un-l dcr side of which is formed a spiralconvolute thread, d; and the cap-piece G provided with an opening, h,and secured in position by the screws s s.

Witnesses: JOHN J. GRANT.

FRED. HAYNES, R. E. RABEAU.

